I have not found a single champion with base stats low enough to justify this.
I don't know the exact amount a level 16 glove gives for flat stats, but as an example, I do have a level 13 6* ATK glove, which gives +181 ATK.
If we assume the scaling applies equally, level 12 ATK % gloves are 40% and level 16 ATK gloves are 60%, IE 1.5x the value. So if we naively took the 181 and scaled it up to level 16, we'd get roughly 270 ATK.
For the 60% ATK glove to be equal, it would require the champ to have a base ATK of 450.
I've looked through all of my level 60 champions - whether they are ATK, DEF, HP, or Support champions, they all have base ATK well over 450. The lowest I've been able to find is Coldheart, with 738 base DEF.
I really feel it would be strange for them to add items into the game whose sole purpose is to be sold. My gut feeling is that they probably didn't do the math properly, because I do agree that their purpose should be for champions who have low base stats.
A great example for this is Sinesha. She's a support champion whose attacks scale off of ATK, but since she's support, her base ATK is quite low - 892, compared to say Corpse Collector, also an ATK champ but with a base ATK of 1167. But the flat ATK would give only 270 ATK, compared to the % ATK giving 535.
The simple solution here would be to just double the stats you get from flat stat items. If they were to do that, it would make the flat ATK glove better for Sinesha than the % one - the flat would give 540, compared to the % giving 535. And for champs with base ATK even lower, it would be even more the case.
